Semiconductor etch residue remover and cleansing compositions

Abstract

An aqueous and semi-aqueous formulation useful for removing post etch and ash residue from Cu low K dielectric semiconductor devices. The composition comprises a polycarboxylic acid buffering system, a fluoride system, water, a water miscible organic solvent for the said aqueous compositions and optionally a chelating agent, a metal corrosion inhibitor and a surfactant.

1 . A cleansing composition for semiconductor devices, selected from aqueous and semi-aqueous compositions, comprising: (a) from about 0.5 to about 20 percent of an organic water soluble polyprotic carboxylic acid, (b) a metal free base in proportion to form an effective buffer with above acid; (c) from about 20 to about 95 percent water; (d) from about 0 to about 60 percent of a water miscible organic solvent; and (e) from about 0.25 to about 5 percent of a fluoride source. 
     
     
         2 . An aqueous cleansing composition for semiconductor devices, in accordance with  claim 1 , comprising: (a) from about 0.5 to about 20 percent of an organic water soluble polyprotic carboxylic acid; (b) a metal free base, in proportion to form an effective buffer with the above acid; (c) about 20 to about 95 percent water; and (d) about 0.25 to about 5 percent of a fluoride source. 
     
     
         3 . A semi-aqueous cleansing composition for semiconductor devices, in accordance with  claim 1 , comprising: (a) about 0.5 to about 20 percent of an organic polyprotic carboxylic acid; (b) a metal free base in proportion to form an effective buffer with the above acid; (c) about 20-60 percent water; (d) about 30-60 percent water miscible organic solvent; and (e) about 0.25 to about 5 percent of a fluoride source. 
     
     
         4 . The cleansing composition of  claim 2  wherein the water soluble polycarboxylic acid is selected from citric acid and tartaric acid and the fluoride source in ammonium fluoride. 
     
     
         5 . The cleansing composition of  claim 2  containing an additive selected from a metal corrosion inhibitor and a chelating agent. 
     
     
         6 . The cleansing composition of  claim 2  incorporating a surfactant. 
     
     
         7 . The cleansing composition of  claim 4  wherein the water soluble polyprotic carboxylic acid is selected from citric acid and tartaric acid. 
     
     
         8 . The semi-aqueous cleansing composition of  claim 3  containing an additive selected from a metal corrosion inhibitor and a chelating agent. 
     
     
         9 . The semi-aqueous cleansing composition of  claim 3  incorporating a surfactant. 
     
     
         10 . The semi-aqueous cleansing composition of  claim 3 , wherein the polycarboxylic acid is tartaric acid and the metal free base is monoethanolamine and the fluoride source is ammonium fluoride. 
     
     
         11 . The semi-aqueous cleaning formulation of  claim 5 , wherein the organic polyprotic carboxylic acid is citric acid, and the formulation contains from about 0.5-20% percent monoethanolamine, and from about 0.25 to about 3 percent ammonium fluoride as the fluoride source. 
     
     
         12 . The aqueous cleansing composition of  claim 10 , wherein the polyprotic carboxylic acid is tartaric acid and is present in amounts from about 0.5 to about 5 percent, the metal free base is monoethanolamine and the ammonium fluoride is present in amounts of from about 0.25 to about 3 percent. 
     
     
         13 . The aqueous cleansing composition of  claim 10 , wherein the polycarboxylic acid is citric acid. 
     
     
         14 . A method of preparing semiconductor etch residue cleaning formulation selected from aqueous and semi-aqueous compositions the steps comprising: (a) introducing into a reaction vessel from about 0.5 to about 20 percent of an organic water soluble polyprotic carboxylic acid and a metal free base in proportion to form an effective buffer with said acid; (b) introducing from about 20 to about 95 percent water into said reaction vessel; and (c) adding at a rate with stirring to prevent clumping from about 0 to about 60 present of a water miscible organic solvent from about 0.25 to about 5 percent of a fluoride source. 
     
     
         15 . A method of preparing an aqueous cleaning formulation for semiconductor devices in accordance with  claim 14 , comprising: (a) introducing about 0.5 to about 20 percent of a mixture of an organic water soluble polyprotic carboxylic acid with the metal free base in proportion to form an effective buffer with said acid into the reaction vessel containing from about 20 to about 25 percent water; and (b) from about 0.025 to about 5 percent of a fluoride source and reacting said mixture. 
     
     
         16 . A method of preparing a semi-aqueous cleaning formulation for semiconductor devices in accordance with  claims 14 , comprising: (a) introducing about 0.5 to about 20 percent of a mixture of an organic polyprotic carboxylic acid with the metal free base in proportion to form an effective buffer with the acid into the reaction vessel containing from about 20-60 percent water; (b) about 30-60 percent water miscible organic solvent; and (c) about 0.25 to about 5 percent of a fluoride source and stirring said mixture until homogeneous.